The present invention relates to locks and locking methods, and more particularly to devices and methods for locking and unlocking vehicle steering columns.
Numerous devices and methods exist for locking a vehicle steering column from movement. Most commonly, such devices and methods prevent the steering column from being rotated to steer the vehicle. The vehicle can be a car, van, truck, motorcycle, bus, or all-terrain vehicle having a number of wheels, a boat with one or more rudders, a snowmobile with skis, a vehicle having one or more tracks, and the like. A steering column lock used in any such vehicle is typically employed to prevent vehicle theft or unauthorized use.
A popular and well-known mechanism for locking a steering column is a lock bolt that is spring-loaded into releasable engagement with a groove or aperture in the steering column. A mechanism is normally provided for retracting the lock bolt against the spring-loaded force to unlock the steering column for vehicle operation. As is well known to those skilled in the art, the mechanism can retract the lock bolt in response to user insertion and turning of a key.
Common design concerns with steering column locks include the ability of a thief or other unauthorized user to release the lock bolt from the steering column (thereby unlocking the steering column), and the ability of the lock bolt to engage and lock the steering column during vehicle operation. Conventional steering column latches fail to address both of these concerns well. By way of example only, a number of steering column lock designs rely only upon a spring to hold the lock bolt in or out of engagement with the steering column. As another example, some steering column locks are more susceptible to tampering, physical manipulation, or force to be moved to their unlocked positions. Also, many conventional steering column locks fail to employ any element or elements positively engaging with the lock bolt to protect against unintentional lock bolt engagement with the steering column (such as during device operation under significant vibration).
Another design concern with steering column locks is device complexity. Increased device complexity leads to increased lock cost and potential for lock operational problems and even malfunction. Accordingly, the relatively complex structures of conventional steering column locks often represent less than optimal lock designs.
In light of the problems and limitations of the prior art described above, a need exists for a steering column lock that is relatively simple, reliably locks and unlocks the steering column, has a lock bolt that is engaged and held in both its locked and unlocked positions, is less susceptible to being unlocked by an unauthorized user, and is protected against unintentional locking even in stressful operating environments. Each preferred embodiment of the present invention achieves one or more of these results.
The present invention provides a manner in which a lock bolt can be engaged and secured in locked and unlocked positions with respect to a steering column. In some preferred embodiments of the present invention, a pawl is movable into and out of engagement with the lock bolt in two different locations on the lock bolt corresponding to two different positions of the lock bolt relative to the steering column: a position in which the lock bolt is extended to lock the steering column and a position in which the lock bolt is retracted to unlock the steering column. The pawl can be movable into and out of engagement with the lock bolt in a number of different manners, but preferably is pivotable about a pivot pin. Preferably, the pawl is connected to an actuator for actuating the pawl into and out of engagement with the lock bolt. The pawl can be manually operated in other embodiments of the present invention.
To establish engagement of the pawl with the lock bolt in some preferred embodiments of the present invention, an engagement portion of the pawl is moved into one of at least two recesses in the lock bolt. In this manner, the engagement portion of the pawl at least prevents retraction of the lock bolt when the lock bolt is in its locked position and extension of the lock bolt when the lock bolt is in its unlocked position. In alternative embodiments, the engagement portion of the pawl can engage with and limit movement of the lock bolt in other manners (such as by being retained between protrusions on the lock bolt).
The lock bolt can have multiple parts or can be a single integral unit. In a preferred embodiment, the lock bolt has a shaft piece for engaging with a steering column and a shuttle piece movable with respect to the shaft piece and with which the pawl engages. Such a multiple-piece lock bolt permits the lock bolt to be moved and retained in a locked position even though the shaft piece is not yet able to engage with the steering column. The lock bolt is preferably normally biased toward engagement with the steering column, and the pawl is preferably normally biased toward engagement with the lock bolt by biasing elements (such as springs, for example).
The steering column lock of the present invention can be used in conjunction with an electronic user identification system such as a conventional passive entry system. An electronic user identification system can be connected to the pawl actuator if desired, and can even be connected to another actuator for extending and retracting the lock bolt in some preferred embodiments. To unlock the steering column lock, the pawl is first retracted from engagement therewith. Preferably, the pawl is retracted only after identification of an authorized user, which can be by an electronic identification process generating a signal to actuate the pawl actuator and to disengage the pawl, the insertion and turning of an authorized key into a conventional lock tumbler mechanically connected to the pawl, and the like. After the pawl has been retracted, the lock bolt can preferably be retracted by a mechanical connection between a rotatable ignition switch and the lock bolt. The lock bolt can instead be retracted in other manners, such as by an electrical connection between an ignition switch and an actuator connected to the lock bolt or by manual retraction by a user. During or after lock bolt retraction, the pawl is preferably extended toward the lock bolt for engagement therewith at a different location on the lock bolt. Such extension can be by the pawl actuator, by manual user manipulation, by a mechanical linkage between the ignition switch and the pawl, and the like. Once engaged by the pawl in the unlocked position, the lock bolt is protected from unintentionally engaging with the steering column even under high vibration and harsh operating conditions.
The steering column lock is preferably locked in a process that is generally the reverse of that just described. The pawl is first retracted by the pawl actuator or in another manner desired, after which time the lock bolt is extended into engagement with the steering column and the pawl is extended again by the pawl actuator (or in another manner) into engagement with the lock bolt at a different location on the lock bolt. By being engaged with the pawl in the locked position, the steering column lock of the present invention is made significantly more difficult to compromise and cannot be forced into an unlocked position without retraction of the pawl (preferably by electronically triggering actuation of the pawl actuator).
The present invention therefore provides an apparatus and method for locking a steering column that is simple, is capable of resisting even forceful attempts to unlock the steering column without authorization, and protects against unintentional locking of the steering column even under stressful operating conditions. More information and a better understanding of the present invention can be achieved by reference to the following drawings and detailed description.